Reversible magnetic gearing



Apri] 17, 1945. G, F, BRAKE 2,373,663

REVERSIBLE MAGNETIC GEARING Filed Nov. 26, 1943 22 Imm.

- Geo/ye %fre5f Dr ,ke

. in the form of a worm I andv available driven elements in the form of worm u are throat cut with their conformity with the outer diameter'oi'- the worm.

longitudinally to Patented Apri 17, 1945 UNITED STATES PATENT oFFlcE REVERSIBLE MAGNETIC GEARINGr George Forrest Drake, Rockford, Ill., assigner to Wood a corporation of Illinois Application November 26, 1943, Serial No. 511,819

9 Claims. (Cl. 172-5284) The present invention pertains to a novel magnetic gearing.

one object of the present invention is to provide a novel 'reversible magnetic gearing.

.another object is to provide a magnetic gearing which will transmit rotary power in either direction depending on which of two .flux paths is energized and which incorporates means for minimizing the eil'ect of flux leakage through Athe inactive flux path.

Further objects and advantages of the invention will become apparent as the following description proceeds, taken in connection with the accompanying drawing in which:

Figure 1 is a vertical sectional view of a rever sible magnetic gearing embodying the present invention.

Fig. 2 is a sectional view taken substantially along the line 2-2 in Fig. l.

Fig. 3 is a transverse sectional view taken sub1x scribe in detail the preferred embodiment, but

it is to be understood that I do not thereby intend to limit the invention to the .specific form disclosed, but intend to cover al1 modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

ward Governor Company, Rockford, Ill.,

lof the worm thread. The'minimum clearance between the coacting opposed faces of the gear' teeth and worm thread is desirably of the order posits direction, assuming unidirectional rotation of the drive worm. In each instance the flux linking the worm Ill with one of the worm gears II, I2 tends to maintain a minimum air gap between them so that the selected worm gear is revoked' by the resulting tendency of its teeth to follow, or remainin registry with, the thread of. the

worm. I l l The worm I0 is shown as journaled in antifriction bearings I3 in the opposite side walls of a suitable non-magnetic housing I4, and may be driven by any suitable power means (not shown) connected to the input shaft I5 (Figs. 2 and 3). 'Ihe driven gears Il, I2 may be connected to a common output .shaft IB (Fig. l) for .driving the latter in one direction or the other naledin antifriction bearings I8 in the end walls Referring more particularly. to the exemplary embodiment of the invention herein illustrated, the improved gearing comprises a driving element gears Il, I2 supported on diametrically opposite sides of the worm with their axesl spaced from andv extending at right angles'A to the worm axis.- Whilefvarious suitable tooth forms may be employed, a helical thread is provided on the worm I0 while the gears II, I2 have spiral teeth which peripheries concaved in The teeth of the tearsA n, n are 'of the same pitches the thread on thevdrive worm and are the worm whose dinally to follow the gear teeth. The gears are similarly curved of the worm. The width of the faces of each gear tooth substantially vmatches the widthof the face match the transverse contour v two alternatively l 20, 2| of the housing. 'I'he shaft I8 is directly connected to the driven shaft I8, while the shaft I1 has' on its outer end a gear 22 meshing with an idler gear 23 which in turn meshes with `a gear 24 on the outer end of the shaft I8. Thus, when-the gear I2 is magnetically coupled to the drive lworm I0, the connection to theshaft I8 is directy through the shaft Il, whereas when the other driven gear -II is magnetically coupled with the drive worm I. the ldrive'connection to the shaftf is completed through the shaft I1 andL gears 22, 23, 2L.

Energizing windings 25, 2i are employed for linking the drive worm I. magnetically with. the

., respective gears I I, I2. Such windings embrace the respective shafts Il, I 8 of the worm gears in ofgmagnetizable material.

` closely spaced relation so that each winding acts when energized to induce .a flow of ilux generally axially through the corresponding shaft. These shafts.' like-the worm and worm gears.,are made Low reluctance paths for the iluxes'inducedby the windings 2l, 2l are completed through a core structure comprising the casing end 2| and a projection 2l made of magnetizable material. The body or side wall portion it of the casing, as well as the casing end wall and end cap 28, are all made of non-magnetic material so as to minimize leakage of flux through them. The ends of the shafts il, itl are extended well within the casing end member 2i (see Fig. 2)A and the projection Elis extended closely adjacent the periphery of the drive worm it at a point substantially midway between the'actve face areas of the `worm gears li, l2. The end face of the projection 2l is concaved in conformity with the contour of the worm so as to minimize the air gap therebetween.

The meanspaths traversed by the fluxes induced by the windings 25, 2t are indicated genarally by the arrow lines A,'B in Fig. 4. .The direction of the ilow of iux i`n either of the paths will, of course, depend upon the direction of ilow of energizing current in the corresponding winding. Such windings may be energized either by direct or alternating current, although the former is preferred. l The yinvention contemplates the provision of means for counteracting any' tendency of the. ux created by the energization of one of the windings to be by-passed from its regular path through the inactive driven gear and produce a torque opposing the torque produced |by` the main ux ow through the intended path. To

avoid such a reduction in the power transmitted,

asvaeee Thel control switch ed and rhecstat 2s as well may be located at a remote point of control as desired.

By way of recapitulation of the operation. it may be assumed that the drive worm. i@ is rotating continuously in a clockwise direction as viewed in Fig. 1. With the control switch 3s v in its mid position, both of the windings 25, 2S are deenergized so that no iux ows and the worm gears l l, l2 and the output shaft i@ remains at rest. Closure of the switch contact 32 energizes the .winding 26 at full voltage, thereby link ing the worm gear l2 magnetically with the drive worm l@ so that the shaft il of this wormgear is rotated counterclcckwise (as, viewed from its upper end in Fig. 3), wherefore the shaft il is likewise revolved counterclockwise. During this time, the worm gear il rotates idly in the same direction as the selected worm gear l2, by reason of their interconnection through the gears 2d,-

23, 22, and such motion of the worm gear li is unopposed by any inadvertent ilux leakage since the low voltage energization of its associated provision is made herein for'partially energizing the winding corresponding to the inactive worm gear at a low potentialas compared to that applied to the one of the active winding and with "a, polarity related to that of the latter winding in such a sense that the iiux induced by the nonf selected winding substantially neutralizes or balances out the leakage ilux which would otherwise tend to ow from the worm l@ to the non-selected one of the driven gears. For this purpose, a rheostatd@ (see Fig. Il)V is included in the circuit, being connected between conductors 30, 3l leading from respective end terminals of the windings to contacts 32, 33 of a selector switch 3d. The movable contact of this selector switch is connected to one supply, line LI while the other supply line L2 is connected through a conductor 35 .tof the interconnected remaining endl terminals of the windings.

when the Switch s4 is in its mid position shown,

both windings 25, 26 are open-circuited. Upon winding 25 neutralizes the flux which tends to leak between the drive worm lll and the worm gear l i.

To cause the shaft I6 to befdriven in the opposite direction, the control switch 3d is thrown to its opposite position closing. the switch contact 33. Thereupon, the winding 25 is energized at full voltage, so that the worm gear l l is linked by ilux withl the drive worm i@ and 'drives the shaft It through the gears 22, 23, 2 in a clockwise direction (as viewed from its upper end).

I claimas my invention: l

1. An electrically controlled reversible gearing comprising in combination, a drive worm, a pair of driven gears, having teeth disposed in closely adjacent non-contacting relation with the thread of the worm on substantially diametrically opposite sides of the latter, said gears being carformingl low reluctance flux paths from saidv shafts to a point on the periphery of the worm closing the switch contact 33, the winding 25 is l connected across the full line voltage, thus inducing a iiow` of flux along the arrow line A to link the drive worm I0 to the driven worm gear Il. At' the same time the othervwinding 26 is connected acrossthe line but in with the frheostat 29 so that it is energized with reduced voltage and -tends to induce a ow of flux along' the pathI indicated by the arrow line B. The

latterv sets up a counter-magnetomotive force electually balancing` out any leakage flux which would otherwise tend to, flow from the drive worm substantially midway between said gear-'aand windings embracing the respective shafts and energizable selectively to induce the ow of flux through one or the otherof said shafts and'fthe gear thereon, each. flow of ux linking the respective gear to the worm'andpassing between the worm and the respective shaft through said core structure. e

2. An electrically controlled reversible gearing comprising in combination, a drive worm having a helical thread, a pair ofdriven gears each having spiral,l teeth of the same pitch as said thread and disposed in closely adjacent noncontacting relation with respect to the thread of the worm, a pair of generally parallel shafts carrying the vrespective gears, said worm and lll to the driven worm gear I2. Similarly.l clure l of the switch blade 35 against the other4 stationary contact 32 connects the winding '26 directly across the line for full energization while the winding 25 is energized in Series With. the TheO- 70. bracingv the respective shafts for inducing flows -ot iiux through lthe respective shafts andthe stat 29 to set up 'a low counter-magnetomotive said. gears and said shafts all being of magnetizable material, a core structure forming low reluctance ilux paths from said shafts to an area Lon the'periphery 'of the worm disposed intermeforce.A Adjustment of. the rheostat. 2 9 serves tir vary the amount of counter-magnetmotive force v set up so lthat the latter lcan beaccurately proportioned to balance -ouexacuy the leakage aux.

diate the active lareas of said. gears, and means includingalternatively available windings emgears thereon.

. 3. The combination pair ot driven worin gears having teeth disposed closely 'adjacent non-contacting relation with of, a. drive wormand arespect to the thread of the worm, both said gears and worm being oi magnetizable material, and windings energizable selectively to induce a ilow of flux linking said Worm with one or the other of said gears.

4. The combination oi a rotatable gear elementa pair o coacting gear members having teeth disposeelclosely adjacent to but spaced from the teeth of said element in registering relation with respect to the latter, said element and members'beine composed oi magnetizable material, means providing'two separate fluir paths through the opposed registering areas ci said element and the respective members, and means selectively operable to produce a flow oi 'nun through' one or the other or said paths and cause the transmission oi' rotary power through said element and a corresponding one of said members.

5. The combination of a revolble element, av

pair of revoluble members, means including a pair oi generally parallel shafts for revolubly supporting said members on substantially diametrically opposite sides ci said element, said shafts, said element and said members being composed of magnetizable material, a generally T-shaped core structure of magnetizalole material disposed with the arms of the 'i' adjacent outer end portions or respective ones oi said shafts and with the stem of the i projecting into close proximity with said element at a point on the latter substantially midway between the opposed areas of said element and members, a pair of energizing windings encircling the respective' shafts for inducing va new of fluir in paths of low reluctance which link respective ones of said members to said element both of which paths are completed through said core structure.

The combination oi a rotatable gear element, a pair of coasting eear mernmrs disposed with their peripheries in. registering relation but out of contact, shafts supporting the respective members, said shafts, said element and said meinbers beine composed-oi magnetic material, means providing separate low reluctance ilus paths through said element and the respective meinbers and along said shafts9 and windings selectivelr enereizabie to create a new o? i'lur: alone I one or the other oi said paths and through the registering areas of said element and the corresponding one of sald'members.

7. The combination or a revoluble gear element,

a pair of revoluble vgear members disposed in closely adjacent non-contacting relation with respeci; to said element, said element and members being composed of magnetizable material, means defining two low reluctance ux paths linking ,said element with the respective members, means 4including apair of windings for inducing a flow of ilux through the respective pathsu and means 4beine composed of magnetioable material, means prf viding two separate ux paths through the opposed registering areas oi? said element and the respective members, and means operable selectively to produce a main nur; flow through one of said paths land e, lesser secondariJ nur; new through the'other path opposing the leakage of Y the main ilus through the latter 9. The combination of a rotatable tear elenient, a pair oi coasting gear members having teeth disposed cltnelgir adjacent ifo-but spaced irom the teeth oi said element in registering relation with respect to the latter, said element and members being composed of maenetiaable rnaterial, means providing two separate paths through the opposed registering areas or said ele- Q@ nient and the respective members, windings en= 45 thelatter path.

ersfizable selectively to produce a main fluir iiow through one of said paths, and means for producins a secondary fluir iiovv in the other path opposing the bypassing ofthe main filer through 

